[ARM][clang] Define feature test macro for the PACBTI-M extension
If the extension string "+pacbti" was given in -march=... or -mcpu=... options the compiler shall define the following preprocessor macros:
__ARM_FEATURE_PAUTH with value 1.
__ARM_FEATURE_BTI with value 1.
This patch is part of a series that adds support for the PACBTI-M extension of
the Armv8.1-M architecture, as detailed here:
https://community.arm.com/arm-community-blogs/b/architectures-and-processors-blog/posts/armv8-1-m-pointer-authentication-and-branch-target-identification-extension
The PACBTI-M specification can be found in the Armv8-M Architecture Reference
Manual:
https://developer.arm.com/documentation/ddi0553/latest
The following people contributed to this patch:
- Momchil Velikov
- Ties Stuij
Reviewed By: miyuki
Differential Revision: https://reviews.llvm.org/D112431